In broad outline, the seats that are presently used in buses and the like, though they provide functional features common to the seat in question, they nevertheless have certain deficiencies, due to the angular shapes of the frame or rear part of the back, as well as due to the accessories included therein, some of which project outward due to their volume, thus implying a risk for passengers.
Regarding the footrests that are known to be hinged in the bottom rear part of the seat, for use by the passenger who is seated behind, though they are collapsible to hide them when their use is not required, or else to make it easier for the passenger to get out of his seat, they have prismatic shapes and supports that rigidize the footrest platform, which also projects from the primitive volume of the seat, offering sharp angles and edges that do not favour at all the paasenger's passive safety, failing to comply with the regulations in force for this purpose.
The area of the headrest of this type of conventional seat remains too rigid at the rear part, upon being too high and rugged the rear frame or casing of the back, precisely because in this area there are normally surrounding recesses with generally vertical bars as a handle. This circumstance also contributes to reducing the passenger's passive safety.
As to the frame or chassis in which the normally two seats are supported and secured, the way and means with which this anchoring is done, are not totally satisfactory because they are open and in a collision even at an average speed, they can previously come loose or after the chasis has been deformed, which implies a high risk for the passenger's passive safety.